1. Field
The following description relates to wireless communication, and more particularly, to a wireless sensor communication method in a network including a plurality of wireless sensor neighbor nodes.
2. Description of Related Art
Wireless sensor communication is a communication method for transmitting sensing information generated from a plurality of sensors (a plurality of neighbor nodes) forming a sensor network via wireless communication to a final destination. Wireless sensor communication is implemented in a shorter range than mobile communication, has a data rate lower than that of the mobile communication, and operates generally on a battery in harsh environments where wired power supply is difficult. Since wireless sensor communication needs to be operated in situations in which power is limited, transmission radio waves also have limited intensity, and a relatively short coverage area is formed. In order to expand the communication area which is limited due to the low transmission power in wireless sensor communication, there is a need for an apparatus corresponding to a mobile communication relay.
IEEE802.15.4 is a standard which defines the physical layer (PHY) and media access control layer (MAC), and further includes a definition of an interface between PHY/MAC layers for lower power communication and upper layers for application service. As for the performance level of wireless sensor communication in IEEE802.15.4, using Offset Quadrature Phase Shift Keying (OQPSK) modulation ensures maximum data rates of 250 kbps, and IEEE802.15.4 does not include a basic channel coding mechanism to provide lower power consumption.
There are various delay elements in data transmission in a contention association period (CAP) of IEEE802.15.4, for example, Backoff and Carrier sensing. A long latency indicates that RF power corresponding to the latency is continuously consumed. Also, when a collision between different neighbor nodes occurs, the same operation needs to be repeated, and thus when there are a plurality of neighbor nodes, transmission performance through CAP is significantly degraded. That is, when a personal area network (PAN) is composed of a plurality of neighbor nodes according to IEEE802.15.4, data transmission through CAP has a number of possible collisions and latency, and thus it is difficult to configure a stable sensor network.